Curable compositions

ABSTRACT

The present invention provides a heat-curable composition gives cured phenolic resin products having excellent flexibility; the present invention relates to a heat-curable composition comprising (A) a vinyl polymer having at least one phenol group at the main-chain terminus and (B) a phenolic resin; the present invention related to a polymer obtainable by reacting (A) a vinyl polymer having at least one phenol group at the main-chain terminus with (C) an aldehyde compound, to a heat-curable composition comprising the polymer.

TECHNICAL FIELD

The present invention relates to a phenolic resin-based heat-curablecomposition.

BACKGROUND ART

Phenolic resins have heretofore been used in a variety of fields such asvarious molding compounds, adhesives, coatings, plywood, and laminatesbut their drawback common to these uses is brittleness.

It is known that polymers having terminal functional groups, when usedin combination with suitable curing agents, give cured productsdisplaying good rubber-like elasticity. The main chains of such knownpolymers having terminal functional groups include polyether polymerssuch as polyethylene oxide; hydrocarbon polymers such aspolyisobutylene, polybutadiene, polyisoprene and polychloroprene,inclusive of hydrogenation products thereof; and polyester polymers suchas polyethylene terephthalate, polybutylene terephthalate,polycaprolactone, etc. and according td the backbone structure and modeof crosslinking, these polymers find application in a variety of uses oftheir own. However, most of them are polymers produced by ionicpolymerization or polycondensation, and few vinyl polymers havingfunctional groups at molecular termini, particularly vinyl polymershaving phenol groups as a functional group, are available for commercialuse.

In the above state of the art, the present invention has for its objectto provide a phenolic-resin-based thermocurable composition giving curedproducts having flexibility.

SUMMARY OF THE INVENTION

The first aspect of the present invention relates to a heat-curablecomposition comprising

-   (A) a vinyl polymer having at least one phenol group at the    main-chain terminus and-   (B) a phenolic resin and    -   to a shaped article as obtainable by curing the composition.

The second aspect of the present invention relates to a polymerobtainable by reacting (A) a vinyl polymer having at least one phenolgroup at the main-chain terminus with (C) an aldehyde compound,

-   -   to a heat-curable composition comprising the polymer,    -   and to a shaped article as obtainable by curing the composition.

The present invention is now described in detail.

DISCLOSURE OF THE INVENTION

The first aspect of the invention will be described below in the firstplace.

The (A) Component Vinyl Polymer Having a Phenol Group

The phenol group in the context of the invention is any group of thegeneral formula (1).—Ar—OH  (1)(wherein Ar represents an unsubstituted or substituted aromatic ring).

The phenolic hydroxyl group of the above phenol group may be located inany of the ortho, meta and para positions with respect to the polymerchain but is preferably located in the para position.

In order that the vinyl polymers may crosslink each other to give acured product, it is essential that the polymer have at least one phenolgroup per molecule, and the preferred number of phenol groups permolecule is 1.1 to 4 on the average.

Furthermore, for the expression of rubber-like elasticity, the phenolgroup must be located at the molecular chain terminus. However, it maybe additionally present in the side chain as well.

The vinyl monomer constituting the main chain of said vinyl polymerhaving a phenol group is not particularly restricted but may be any ofvarious monomers. As examples, there may be mentioned (meth)acrylicmonomers such as (meth)acrylic acid, methyl (meth)acrylate, ethyl(meth)acrylate, n-propyl (meth)acrylate, isopropyl (meth)acrylate,n-butyl (meth)acrylate, isobutyl (meth)acrylate, tert-butyl(meth)acrylate, n-pentyl (meth)acrylate, n-hexyl (meth)acrylate,cyclohexyl (meth)acrylate, n-heptyl (meth)acrylate, n-octyl(meth)acrylate, 2-ethylhexyl (meth)acrylate, nonyl (meth)acrylate, decyl(meth)acrylate, dodecyl (meth)acrylate, phenyl (meth)acrylate, toluyl(meth)acrylate, benzyl (meth)acrylate, 2-ethoxyethyl (meth)acrylate,3-methoxybutyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate,2-hydroxypropyl (meth)acrylate, stearyl (meth)acrylate, glycidyl(meth)acrylate, 2-aminoethyl (meth)acrylate,γ-(methacryloyloxypropyl)trimethoxysilane, (meth)acrylic acid-ethyleneoxide adducts, trifluoromethylmethyl (meth)acrylate,2-trifluoromethylethyl (meth)acrylate, 2-perfluoroethylethyl(meth)acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth)acrylate,2-perfluoroethyl (meth)acrylate, perfluoromethyl (meth)acrylate,diperfluoromethylmethyl (meth)acrylate,2-perfluoromethyl-2-perfluoroethylmethyl (meth)acrylate,2-perfluorohexylethyl (meth)acrylate, 2-perfluorodecylethyl(meth)acrylate and 2-perfluorohexadecylethyl (meth)acrylate; styrenicmonomers such as styrene, vinyltoluene, α-methylstyrene, chlorostyrene,styrenesulfonic acid and salts thereof; fluorine-containing vinylmonomers such as perfluoroethylene, perfluoropropylene and vinylidenefluoride; silicon-containing vinyl monomers such asvinyltrimethoxysilane and vinyltriethoxysilane; maleic anhydride, maleicacid and monoalkyl esters and dialkyl esters of maleic acid; fumaricacid and monoalkyl esters and dialkyl esters of fumaric acid; maleimidemonomers such as maleimide, methylmaleimide, ethylmalemide,propylmaleimide, butylmaleimide, hexylmaleimide, octylmaleimide,dodecyimaleimide, stearylmaleimide, phenylmaleimide andcyclohexylmaleimide; nitrile-containing vinyl monomers such asacrylonitrile and methacrylonitrile; amido-containing vinyl monomerssuch as acrylamide and methacrylamide; vinyl esters such as vinylacetate, vinyl propionate, vinyl pivalate, vinyl benzoate and vinylcinnamate; alkenes such as ethylene and propylene; conjugated dienessuch as butadiene and isoprene; vinyl chloride, vinylidene chloride,allyl chloride, allyl alcohol and so forth. These may be used singly ora plurality of them may be copolymerized. The expression “(meth)acrylicacid”, for instance, as used herein above and below means “acrylic acidand/or methacrylic acid”.

Within the above monomer, the main chain obtained by polymerizing a(meth)acrylic monomer or a styrenic monomer is preferred. The morepreferred are (meth)acrylate monomers and the still more preferred areacrylate monomers. Moreover, from the standpoint of physical properties,(meth)acrylic polymers synthesized using not less than 40 weight % of a(meth)acrylic monomer is more preferred.

The molecular weight distribution of the vinyl polymer having at leastone phenol group, that is to say the ratio (Mw/Mn) of weight averagemolecular weight (Mw) to number average molecular weight (Mn), is notparticularly restricted. However, in order to hold the viscosity of thecurable composition low enough to facilitate handling and yet impartsatisfactory physical properties to the cured product, the molecularweight distribution is desirably as narrow as possible. The distributionvalue is preferably less than 1.8, more preferably not more than 1.7,still more preferably not more than 1.6, yet more preferably not morethan 1.5, further more preferably not more than 1.4, and most preferablynot more than 1.3. The molecular weight distribution can be determinedby gel permeation chromatography (GPC) which is the most generaldetermination method. Thus, using chloroform as the mobile phase andpolystyrene gels as the column packing, the number average molecularweight can be measured in polystyrene equivalent.

The number average molecular weight of said vinyl polymer having atleast one phenol group is not particularly restricted but is preferablywithin the range of 500 to 100000. When the molecular weight is lessthan 500, the intrinsic characteristics of vinyl polymers can hardly beexpressed. On the other hand, when the molecular weight exceeds 100000,the polymer is not easy to handle.

The vinyl polymer having a phenol group can be synthesized by variouspolymerization techniques and said techniques is not particularlyrestricted. However, from the standpoint of monomer availability andease of reaction control, the radical polymerization method ispreferred.

The radical polymerization method can be divided into the “generalradical polymerization method” in which a monomer having a givenfunctional group is simply copolymerized with a vinyl monomer using anazo or peroxide compound as the polymerization initiator and the“controlled radical polymerization method” which is capable ofintroducing a given functional group into a defined position such as themolecular terminus.

The “general radical polymerization method” is an expedient method andcan be used for purposes of the present invention. However, by thismethod, a monomer having a given functional group is introduced into theproduct polymer only in probabilities, and in order to synthesize apolymer of high functionality, this monomer must be used in a fairlylarge amount. When conversely the amount of the monomer is small, theratio of polymer molecules not provided with the particular functionalgroup is increased. Another disadvantage is that, since the reaction isa free radical polymerization reaction, the molecular weightdistribution is more or less broadened so that only a polymer having ahigh viscosity can be obtained. On the other hand, the “controlledradical polymerization method” can be divided into the “chain transferagent technique” in which a vinyl polymer having a functional group at aterminus is produced by carrying out the polymerization using a chaintransfer agent having a given functional group, and the “living radicalpolymerization technique” in which the polymerization proceeds with thegrowing chain terminus not being interrupted by a termination reactionto give a polymer approximating the designed molecular weight.

The “chain transfer agent technique” is capable of giving a polymer ofhigh functionality and can be used in the present invention but a chaintransfer agent having a given functional group must be used in a fairlylarge amount relative to the initiator, with the consequent disadvantagein economics inclusive of the cost of treatment involved. A furtherdisadvantage of the technique is that because it is also a free radicalpolymerization method as is said “general radical polymerizationmethod”, there can be obtained only a polymer having a broad molecularweight distribution and a high viscosity.

Unlike the above polymerization technology, the “living radicalpolymerization technique” is advantageous in that despite its also beinga method for radical polymerization reaction which is generallyconsidered to be hardly controllable because of the high velocity ofpolymerization and high incidence of a termination reaction byradical—radical coupling or the like, a termination reaction does noteasily take place, thus giving a polymer with a narrow molecular weightdistribution (Mw/Mn=about 1.1 to 1.5), and further in that the molecularweight can be freely controlled by adjusting the monomer-initiatorcharge ratio. Since it is thus capable of giving a polymer having anarrow molecular weight distribution profile and a low viscosity andenables introduction of a monomer having a given functional group in analmost planned position the “living radical polymerization” is a furtherpreferred method for producing said vinyl polymer having a givenfunctional group according to the present invention.

In a narrow sense of the term, “living polymerization” means apolymerization in which the molecule grows with its terminus beingconstantly activated. Generally, however, the term is used to broadlycover as well a pseudo-living polymerization reaction in which thepolymer grows while molecules with an activated terminus and moleculeswith an inactivated terminus are in equilibrium, and the term as used inthis specification also has the latter broad meaning.

Recently, “living radical polymerization” has been studied in earnest bymany research groups. By way of illustration, this technology includesthe method employing a cobalt porphyrin complex as described in J. Am.Chem. Soc., 116, 7943 (1994); the method using a radical scavenger suchas a nitroxide compound as described in Macromolecules, 27, 7228 (1994),and the atom transfer radical polymerization (ATRP) method using anorganohalogen compound as the initiator and a transition metal complexas the catalyst.

Among such versions of the “living radical polymerization method”, the“atom transfer radical polymerization” method in which a vinyl monomeris polymerized using an organohalogen compound or a sulfonyl halidecompound as the initiator and a transition metal complex as the catalystis still more preferred for the production of said vinyl polymer havinga given functional group because, in addition to the above-mentionedadvantages of “living radical polymerization”, it is capable of giving apolymer having a halogen or the like at its terminus, which iscomparatively favorable for a functional group exchange reaction, andoffers a broad freedom in the initiator and catalyst design. Regardingthis atom transfer radical polymerization method, reference can be madeto Matyjaszewski et al.: J. Am. Chem. Soc., 117, 5614 (1995),Macromolecules, 28, 7901 (1995), Science, 272, 866 (1996), WO 96/30421,WO 97/18247, and Sawamto et al. Macromolecules, 28, 1721 (1995), amongothers.

The initiator for use in the polymerization reaction is not particularlyrestricted but includes, for example, organohalogen compounds,particularly activated organohalogen compounds (e.g. ester compoundshaving a halogen in the α-position and compounds having a halogen in thebenzyl moiety), and halogenated sulfonyl compounds. Using such acompound as the initiator, a halogen-terminated vinyl polymer can beobtained. By converting this terminal halogen in the manner describedbelow, an alkenyl-terminated vinyl polymer can be obtained. Specificexamples of said initiator include; C₆H₅—CH₁X, C₆H₅—C(H)(X)CH₃,C₆H₅—C(X)(CH₃)₂ (wherein C₆H₅ represents a phenyl group; X representschloro, bromo or iodo); R¹—C(H)(X)—CO₂R², R₁—C(CH₃)(X)—CO₂R²,R¹—C(H)(X)—C(O)R², R¹—C(CH₃)(X)—C(O)R² (wherein R¹ and R² may be thesame or different and each represents hydrogen, an alkyl group of 1 to20 carbon atoms, an aryl group of 6 to 20 carbon atoms or an aralkylgroup of 7 to 20 carbon atoms; X represents chloro, bromo or iodo);R¹—C₆H₄—SO₂X (wherein R¹ represents hydrogen, an alkyl group of 1 to 20carbon atoms, an aryl group of 6 to 20 carbon atoms or an aralkyl groupof 7 to 20 carbon atoms; X represents chloro, bromo or iodo).

As the initiator, it is also possible to use an organohalogen compoundor halogenated sulfonyl compound having a functional group other thanthe functional group taking charge of initiation of polymerization. Inthis case, there is obtained a polymer having said functional group ofthe initiator at one of the main chain termini and a halogen atom at theother terminus. As examples of said functional group, there can bementioned alkenyl, crosslinkable silyl, hydroxyl, epoxy, amino, amidoand carboxyl.

The organohalogen compound having an alkenyl group is not particularlyrestricted but includes compounds having the structure represented bythe general formula (2), among others.R⁴R⁵C(X)═R⁶—R⁷—C(R³)═CH₂  (2)(wherein R³ represents hydrogen or a methyl group; R¹ and R⁵ eachrepresents hydrogen or a monovalent alkyl group of 1 to 20 carbon atoms,an aryl group of 6 to 20 carbon atoms or an aralkyl group of 7 to 20carbon atoms, or R¹ and R⁵ may be jointed to each other through theirfree ends; R⁶ represents —C(O)O— (ester group), —C(O)— (keto group), oran o-, m- or p-phenylene group; RX represents a direct bond or adivalent organic group of 1 to 20 carbon atoms which may optionallycontain one or more ether linkages; X represents chloro, bromo or iodo).

Specifically, R¹ and R⁵ each includes hydrogen, methyl, ethyl, n-propyl,isopropyl, butyl, pentyl and hexyl, among others. R¹ and R⁵ may bejointed to each other through their free ends to form a cyclicstructure.

As the organohalogen compound having an alkenyl group, compounds of thefollowing general formula (3) can be further mentioned.H₂C═C(R³)—R⁷—C(R⁴)(X)—R⁸—R⁵  (3)(wherein R³, R⁴, R⁵ and R⁷ are as defined above; R⁸ represents a directbond, —C(O)O— (ester group), —C(O)— (keto group), or an o-, m- orp-phenylene group; X is as defined above).

R⁷ represents either a direct bond or a divalent organic group of 1 to20 carbon atoms (optionally containing 1 or more ether linkages).However, when R⁷ is a direct bond, the vinyl group is attached to thecarbon to which the halogen is attached, thus forming an allyl halide.Since, in this case, the carbon-halogen bond has been activated by theadjacent vinyl group, R⁸ need not necessarily be a C(O)O group or aphenylene group but may be a direct bond. When R⁷ is not a direct bond,R⁸ is preferably a C(O)O group, a C(O) group or a phenylene group inorder that the carbon-halogen bond may be activated.

Specific examples of the halogenated sulfonyl compound having an alkenylgroup include, for example;

-   o-, m- or p-CH₂═CH—(CH₂)_(n)—C₆H₄—SO₂X,-   o-, m- or p-CH₂═CH—(CH₂)_(n)—O—C₆H₄—SO₂X,    (in each formula, X represents chloro, bromo or iodo; n represents    an integer of 0 to 20).

The organohalogen compound having a crosslinkable silyl group is notparticularly restricted but includes compounds having the structurerepresented by the following general formula (4), among others.R⁴R⁵C(X)—R⁶—R⁷—C(H)(R³)CH₂—[Si(R⁹)_(2-b)(Y)_(b)O]_(n)—Si(R¹⁰)_(3-a)(Y)_(a)  (4)(wherein R³, R⁴, R⁵, R⁶, R⁷ and X are as defined above; R⁹ and R¹⁰ eachrepresents an alkyl group of 1 to 20 carbon atoms, an aryl group of 6 to20 carbon atoms, an aralkyl group of 7 to 20 carbon atoms, or atriorganosiloxy group of the formula R′₃SiO— (R′ represents a monovalenthydrocarbon group of 1 to 20 carbon atoms and the 3 R′ groups may be thesame or different); when 2 or more R⁹ or R¹⁰ groups are present, theymay be the same or different; Y represents a hydroxyl group or ahydrolyzable group and when two or more Y groups exist, they may be thesame or different; a is equal to 0, 1, 2 or 3; b is equal to 0, 1 or 2;m represents an integer of 0 to 19; provided, however, that thecondition of a+mb≧1 is satisfied).

The organohalogen compound having a crosslinkable silyl group furtherincludes compounds having the structure represented by the generalformula (5).(R¹⁰)_(3-a)(Y)_(a)Si—[OSi(R⁹)_(2-b)(Y)_(b)]_(m)—CH₂—C(H)(R³)—R⁷—C(R⁴)(X)—R⁹—R⁵  (5)(wherein R³, R⁴, R⁵, R⁷, R⁸, R⁹, R¹⁰, a, b, m, X and Y are as definedabove).

The organohalogen compound or halogenated sulfonyl compound having ahydroxyl group is not particularly restricted but includes compounds ofthe following formula:HO—(CH₂)_(n)—OC(O)C(H)(R)(X)(wherein X represents chloro, bromo or iodo; R represents hydrogen, analkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 20 carbonatoms or an aralkyl group of 7 to 20 carbon atoms; n represents aninteger of 1 to 20).

The organohalogen compound or halogenated sulfonyl compound having anamino group is not particularly restricted but includes compounds of thefollowing formula.H₂N—(CH₂)_(a)—OC(O)C(H)(R)  (X)(wherein X represents chloro, bromo or iodo; R represents hydrogen, analkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 20 carbonatoms or an aralkyl group of 7 to 20 carbon atoms; n represents aninteger of 1 to 20).

The organohalogen compound or halogenated sulfonyl compound having anepoxy group is not particularly restricted but includes compounds of thefollowing formula:

(wherein X represents chloro, bromo or iodo; R represents hydrogen, analkyl group of 1 to 20 carbon atoms, an aryl group of 6 to 20 carbonatoms or an aralkyl group of 7 to 20 carbon atoms; n represents aninteger of 1 to 20).

Furthermore, the polymerization reaction may be carried out using anorganohalogen compound or sulfonyl halide compound having 2 or moreinitiation points as the initiator. In such a case, a vinyl polymerhaving 2 or more halogen atoms per molecule can be obtained.

The initiator having 2 or more initiation sites include but is notrestricted to the following compounds.

(Referring to the above formulas, C₆H₄ represents a phenylene group; Xrepresents chloro, bromo or iodo; R represents an alkyl group of 1 to 20carbon atoms, an aryl group of 6 to 20 carbon atoms or an aralkyl groupof 7 to 20 carbon atoms; n represents an integer of 0 to 20);

(In the above formulas, X represents chloro, bromo or iodo; a representsan integer of 0 to 20; C₆H₄ represents a phenylene group).

The transition metal complex which can be used as the catalyst for saidatom transfer radical polymerization includes complexes of center metalsbelonging to Groups 7, 8, 9, 10 and 11 of the Periodic Table of theElements. As preferred examples, complex compounds of zero-valent copper(Cu⁰), monovalent copper, divalent ruthenium, divalent iron or divalentnickel can be mentioned. The preferred, among these, are complexes ofcopper. As specific compounds of monovalent copper, there can bementioned cuprous chloride, cuprous bromide, cuprous iodide, cuprouscyanide, cuprous oxide, cuprous perchlorate, and so on. When a coppercomplex is used, its catalytic activity can be increased by adding, asthe ligand, 2,2-bipyridyl or its derivative, 1,10-phenanthroline or itsderivative and a polyamine such as tetramethylethylenediamine,pentamethyldiethylenetriamine, hexamethyltris(2-aminoethyl)amine or thelike. The tris(triphenylphosphine) complex of divalent rutheniumchloride (RuCl₂(PPh₃)₃) is also suited as the catalyst. When a rutheniumcomplex is used as the catalyst, an aluminum alkoxide may be added asthe activator. Also suited as the catalyst are thebis(triphenylphosphine) complex of divalent iron (FeCl₂(PPh₃)₂),bis(triphenylphosphine) complex of divalent nickel (NiCl₂(PPh₃)₂), andbis(tributylphosphine) complex of divalent nickel (NiBr₂(PBu₃)₂).

The vinyl monomer for use in this polymerization is not particularlyrestricted but all the monomers mentioned hereinbefore can be used withadvantage.

The above polymerization reaction can be conducted in the absence of asolvent or in the presence of a solvent selected from a broad range. Thesolvent which can be used thus includes hydrocarbon solvents such asbenzene, toluene, etc.; ether solvents such as diethyl ether,tetrahydrofuran, diphenyl ether, anisole, dimethoxybenzene, etc.;halogenated hydrocarbon solvents such as methylene chloride, chloroform,chlorobenzene, etc.; ketone solvents such as acetone, methyl ethylketone, methyl isobutyl ketone, etc.; alcohol solvents such as methanol,ethanol, propanol, isopropyl-alcohol, n-butyl alcohol, tert-butylalcohol, etc.; nitrile solvents such as acetonitrile, propionitrile,benzonitrile, etc.; ester solvents such as ethyl acetate, butyl acetate,etc.; and carbonate solvents such as ethylene carbonate, propylenecarbonate, etc.; among others. These can be used independently or two ormore of them can be used as a blend. Moreover, the polymerizationreaction can be carried out in an emulsion system or a system usingsupercritical fluid CO₂ as the medium.

The polymerization can be carried out within the temperature range of 0to 200° C., preferably at room temperature to 150° C.

The vinyl polymer having at least one phenol group can be prepared bythe following procedures, however these products are not restrictedthereto.

(A) The method comprising introducing a phenol group directly into thevinyl polymer at synthesis of the polymer by radical polymerization.

(B) The method starting with a vinyl polymer having at least one halogenwherein a phenol group-containing functional group is substituted forthe halogen.

The first method of synthesis (A) comprising introducing a phenol groupdirectly into the polymer is not particularly restricted but includesthe following specific procedures (A-a) and (A-b), among others.

(A-a) In synthesizing a vinyl polymer by living radical polymerization,not only a predetermined vinyl monomer but also a compound having both apolymerizable alkenyl group and a phenol group per molecule, such as acompound of the following general formula (6), is reacted.CH₂═C(R¹¹)—C₆H₄—OH  (6)(wherein R¹¹ represents hydrogen or an organic group containing 1 to 10carbon atoms).

The species of the compound of the general formula (6) is notparticularly restricted but is preferably vinylphenol.

In case the phenol group may interfere with the reaction, the phenolgroup may have been protected with a suitable protective group. As suchcompounds, alkoxystyrene monomers such as p-t-butoxystyrene can bementioned.

The timing of reacting said compound having both a polymerizable alkenylgroup and a phenol group is not particularly restricted but in theliving radical polymerization, this compound is preferably reacted as asecondary monomer in the terminal stage of the polymerization reactionor after completion of reaction of the given monomer.

(A-b) In synthesizing a vinyl polymer by living radical polymerization,said compound having both a less-polymerizable alkenyl group and aphenol group is reacted as a secondary monomer in the terminal stage ofthe polymerization reaction or after completion of reaction of the givenmonomer.

Such compound is not particularly restricted but includes allylphenoland allyloxyphenol, among others. In case the phenol group may interferewith the reaction, it may be protected with a suitable protective groupin advance.

In the method of synthesis (A) wherein a vinyl polymer having at leastone phenol group is produced by direct introduction of the phenol group,the procedure (A-b) is preferred in view of the ease with which thenumber of units of the phenol group to be introduced per molecule can beeasily controlled.

The preferred method for synthesizing a vinyl polymer having at leastone halogen for use in the above method of synthesis (B) is the atomtransfer radical polymerization technique. The method of substituting aphenol group-containing functional group for the halogen of this polymeris not particularly restricted but includes, for example, thesubstitution method for halogen comprising reacting a vinyl polymerhaving at least one highly reactive carbon-halogen bond with an oxyanionsuch as the one represented by the following formula (7) or (8).HO—C₆H₄—R¹²—O⁻M⁺  (7)HO—C₆H₄—R¹²—C(O)O⁻M⁺  (8)(wherein R¹² represents a C₁₋₂₀ divalent organic group optionallycontaining a direct bond or an ether linkage; M⁺ represents an alkalimetal ion or a quaternary ammonium ion).

As the oxyanion to be used, a phenol group-containing carboxylate anionis more preferred.

The oxyanion of the above general formula (71 or (8) can be obtained bycausing a basic compound to act on the corresponding precursor andabstracting the active proton.

The precursor compound mentioned above includes catechol, resorcinol,hydroquinone and hydroxybenzoic acid.

Specific examples of the alkali metal ion include the lithium ion,sodium ion and potassium ion and, as the quaternary ammonium ion, theremay be mentioned the tetramethylammonium ion, tetraethylammonium ion,trimethylbenzylammonium ion, trimethyldodecylammonium ion andtetrabutylammonium ion.

As such basic compounds, there may be mentioned the following:

Alkali metals such as sodium, potassium and lithium; metal alkoxidessuch as sodium methoxide, potassium methoxide, lithium methoxide, sodiumethoxide, potassium ethoxide, lithium ethoxide, sodium tert-butoxide andpotassium tert-butoxide; carbonates such as sodium carbonate, potassiumcarbonate, lithium carbonate and sodium hydrogen carbonate; hydroxidessuch as sodium hydroxide and potassium hydroxide; hydrides such assodium hydride, potassium hydride, methyllithium and ethyllithium;organometals such as n-butyllithium, tert-butyllithium, lithiumdiisopropylamide and lithium hexamethyldisilazide; ammonia; alkylaminessuch as trimethylamine, triethylamine and tributylamine; polyamines suchas tetramethylethylenediamine and pentamethyldiethylenetriamine;pyridine compounds such as pyridine and picoline, etc.

The basic compound is used in an equivalent amount or in a slight excessrelative to the precursor substance, preferably in an amount or 1 to 1.2equivalents.

A quaternary ammonium salt may also be used as the above oxyanion. Inthis ca se, it can be obtained by preparing an alkali metal salt of acarboxylic acid compound and reacting this with a quaternary ammoniumhalide. As examples of the quaternary ammonium halide, there may bementioned tetramethylammonium halides, tetraethylammonium halides,trimethylbenzylammonium halides, trimethyldodecylammonium halides andtetrabutylammonium halides.

As the solvent to be used in reacting the above precursor with a basiccompound, there may be mentioned hydrocarbon solvents such as benzeneand toluene; ether solvents such as diethyl ether, tetrahydrofuran,diphenyl ether, anisole and dimethoxybenzene; halogenated hydrocarbonsolvents such as methylene chloride and chloroform; ketone solvents suchas acetone, methyl ethyl ketone and methyl isobutyl ketone; alcoholsolvents such as methanol, ethanol, propanol, isopropanol, n-butylalcohol and tert-butyl alcohol; nitrile solvents such as acetonitrile,propionitrile and benzonitrile; ester solvents such as ethyl acetate andbutyl acetate; carbonate solvents such as ethylene carbonate andpropylene carbonate; amide solvents such as dimethylformamide anddimethylacetamide; sulfoxide solvents such as dimethyl sulfoxide; and soon. These may be used singly or two or more of them may be used inadmixture.

The method of synthesizing said vinyl polymer having at least one highlyreactive carbon-halogen bond is not particularly restricted butincludes, among others, the method using a halide, e.g. carbontetrachloride, ethylene chloride, carbon tetrabromide or methylenebromide, as the chain transfer agent in radical polymerization asdescribed in Japanese Kokai Publication Hei-4-132706 (chain transferagent technique) and the method for radical polymerization of a vinylmonomer using an organic halide having at least one highly reactivecarbon-halogen bond or a sulfonyl halide as the initiator and atransition metal complex as the catalyst (atom transfer radicalpolymerization technique). The polymers obtainable by the above twomethods invariably have a terminal carbon-halogen bond and, therefore,both methods are useful for the production of phenol group-terminatedvinyl polymers. However, particularly in view of the ease of controlover molecular weight and molecular weight distribution, the lattertechnique, i.e. atom transfer radical polymerization technique, ispreferred.

The (B) Component Phenolic Resin

The (B) component phenolic resin may be a known resin. Thus, theresol-type or novolac-type phenol resins which are obtainable by thecondensation reaction of a phenolic compound, such as phenol, cresol,xylenol, resorcinol, an alkylphenol and a modified phenol (e.g. cashewoil-modified phenol, tall oil-modified phenol, etc.) with an aldehydecompound such as formalin, paraformaldehyde and the like, andnitrogen-containing phenolic resins obtainable by said reaction of thephenolic compounds with said aldehyde where an ammonia- or amine-basedcompound is used as a catalyst. These may be used each independently oroptionally a mixture of two or more of them can be employed.

The mixing ratio of phenol-terminated vinyl polymer (A) and phenolicresin (B) is not particularly restricted but can be adjusted accordingto the intended use of the cured product. Generally speaking, the ratioof (A) component to (B) component is not particularly restricted but is0.01 to 0.99, preferably 0.05 to 0.95. For example, when it is intendedto improve the impact resistance, flexibility, toughness and peelstrength of cured phenolic resins, the phenol-terminated vinyl polymer(A) can be added in a small proportion to phenolic resin (B). Forimproving the strength of the cured resin, the amount of phenolic resin(B) may be increased. While the heat-curable composition of theinvention gives a cured product having excellent rubber-like elasticity,it may give a broad range of products from a rubbery cured product to aresinous cured product depending on the ratio of both components.

When a novolac resin is used as phenolic resin (B), an aldehyde or thelike compound is preferably used as the curing agent. As the aldehydecompound, the compounds mentioned later herein can be employed.

Where necessary, the heat-curable composition of the invention may besupplemented with various fillers, plasticizers, antioxidants, UVabsorbers, lubricants, pigments, forming agents, and so forth.

When a filler is used as an additive, such a filler as generally used inphenolic resins, namely woodmeal, pulp, cotton chips, asbestos, glassfiber, mica, walnut shell flour, rice hull flour, graphite, diatomaceousearth, clay, etc., can be employed with advantage. Such other fillers asfumed silica, precipitated silica, silicic anhydride, carbon black,calcium carbonate, clay, talc, titanium oxide and magnesium carbonatemay also be used. These fillers may be used singly or two or more ofthem may be used in admixture.

The properties of the cured product depend on the main chain structureand molecular weight of the (A) component phenol group-terminated vinylpolymer as well and may range broadly from those of a rubber product tothose of a resin product.

The method of molding the heat-curable composition is not particularlyrestricted but when the cured product is to be rubber-like, the methodin routine use for the molding of rubber-type liquid polymers ispreferably employed. Molding by such a method may give an adhesive,sealant, rubbery shaped article or rubber-like foam with improvedstrength. On the other hand, when the cured product is to be resinous,it is preferable to employ a molding method in routine use for themolding of phenolic resins, such as compression molding, transfermolding or injection molding. The shaped articles produced by any ofthese molding methods also belong to the first aspect of the presentinvention.

As typical uses for the heat-curable composition according to theinvention, there can be mentioned various sealants, adhesives,self-adhesives, elastic adhesives, coatings, powder coatings, foams,electric/electronic potting agents, films, gaskets, plywood, laminates,molding compounds, artificial marble, copper-clad laminates, reinforcedwood, phenol resin foam, binders for fiber-boards or particle boards,shell mold binders, brake lining binders, glass fiber binders, and soon.

The second aspect of the present invention is now described.

The polymer according to the second aspect of the invention is a vinylpolymer having a resol-type or novolac-type phenol resin structure atits terminus as formed by the condensation reaction of (A) a vinylpolymer having at least one phenol group at the main-chain terminus with(C) an aldehyde compound. This phenol-terminated vinyl polymer (A) isthe same as the one described hereinbefore.

The aldehyde compound (C) for use in this invention is not particularlyrestricted but any of the aldehyde compounds that have heretofore beenused as starting materials for phenolic resins in general can be usedwith advantage.

The aldehyde compound in the context of this invention means a class ofcompounds which are recognized by those concerned with phenolic resinsto be aldehyde compounds.

The aldehyde compound includes but is not limited to formaldehyde,hexamethylenetetramine, paraformaldehyde, furfural, acetaldehyde,salicylaldehyde and other aldehydes mentioned under the heading of“ALDEHYDES” on page 30 of Plastic Gijutsu Zensho (Encyclopedia ofPlastic Technology) 15, Phenol Resin (authored by Uenaka, KogyoChosakai). These can be used each independently or optionally in acombination of two or more different species. As the aldehyde compounds,formaldehyde and hexamethylenetetramine are preferred. Formaldehyde isgenerally used in the form of formalin. While hexamethylenetetramine isin routine use as a curing agent for novolac-type phenolic resins inparticular, it functions as a crosslinking agent in a curing reactionsystem according to a reaction mechanism similar to that offormaldehyde.

The ratio of aldehyde compound (C) to phenol group-terminated vinylpolymer (A) is not particularly restricted but can be judiciouslyselected according to the performance characteristics required of thepolymer. Generally, however, the number of aldehyde groups which shouldbe available per phenol group of polymer (A) is preferably 0.3 to 10,more preferably 0.6 to 5.0.

While the polymer according to the second aspect of the presentinvention is formed on the condensation reaction between components (A)and (C), this reaction may be conducted adding a catalyst and a solventwhere necessary.

As the catalyst, any of the catalysts in use for the production of knownphenolic resins can be used with advantage. The catalyst which can beused generally includes inorganic or organic acids and bases, such ashydrochloric acid, oxalic acid, formic acid, acetic acid,orthophosphoric acid, butyric acid, lactic acid, boric acid,p-toluenesulfonic acid, benzenesulfonic acid, sodium hydroxide,potassium hydroxide, hexamethylenetetramine, aqueous ammonia,trimethylamine, triethylamine, pyridine and calcium hydroxide, amongothers. When ammonia or an amine compound is used as the catalyst, anitrogen-containing phenolic resin is obtained.

The solvent is not particularly restricted but may be the commonsolvent, although alcohols such as methanol are preferred. Depending onthe intended application, xylene, toluene, methyl ethyl ketone or thelike can also be employed. These solvents can be used each independentlyor optionally in a combination of two or more different species.

Furthermore, the above condensation reaction may be carried out addingthe phenolic compound (the (D) component). The (D) component is notparticularly restricted but any of the phenolic compounds in use for theproduction of known phenolic resins can be used with advantage. Specificexamples thereof include phenol, cresol, xylenol, resorcinol,alkylphenols and modified phenols (e.g. cashew oil-modified phenol, talloil-modified phenol, etc.). By adjusting the formulating ratio of (A)and (D) components, a broad range of novel phenolic resins can beliberally prepared.

The conditions of condensation reaction for producing the polymeraccording to the second aspect of the invention may be those in routineuse for the production of known phenolic resins but when the polymer (A)to be used contains two or more phenol groups per molecule, the reactiontemperature and time must be judiciously controlled, for otherwise thesystem tends to undergo gelation with the progress of condensation.

The polymer according to the second aspect of the invention may beprocessed into a heat-curable composition comprising the polymer. Suchheat-curable composition also belongs to the second aspect of theinvention. This heat-curable composition may be supplemented with saidfiller, plasticizer, antioxidant, ultraviolet absorber, lubricant,pigment, forming agent, etc. where necessary.

When the polymer according to the second aspect of the invention is anovolac-type polymer, it is preferred to use a curing agent such as analdehyde compound for curing. The aldehyde compound which can be usedincludes the compounds mentioned hereinbefore.

The properties of the cured product depend on the main chain structureand molecular weight of the phenol group-terminated vinyl polymer (A) aswell and a broad range of products from rubbery ones to resinous onescan be produced as desired.

The method of molding the heat-curable composition according to thesecond aspect of the invention is not particularly restricted. However,when the cured product is to have rubber-like properties, the molding ispreferably carried out by a technique in routine use for the molding ofrubbery liquid polymers. By such a molding technique, adhesives,sealants, rubber-like shaped articles, rubber-like foams, etc. withimproved strength can be obtained. On the other hand, when the curedproduct is to have resinous properties, the molding is preferablycarried out by a technique in routine use for the molding of phenolicresins, such as compression molding, transfer molding and injectionmolding. The shaped articles thus produced also belong to the secondaspect of the present invention.

Specific exemplary applications of the beat-curable compositionaccording to the second aspect of the invention include sealants,adhesives, self-adhesives, elastic adhesives, coatings, powder coatings,foams, electric/electronic potting agents, films, gaskets, plywood,laminates, molding compounds, artificial marble, copper-clad laminates,reinforced wood, phenolic resin foam, binders for fiber-boards orparticle boards, shell mold binders, brake lining binders, glass fiberbinders, and so on.

BEST MODE FOR CARRYING OUT THE INVENTION

The following examples and comparative examples illustrate the presentinvention in further detail, it being, however, to be understood thatthese examples are by no means limitative of the scope of the invention.

As referred to in the following examples, the “number average molecularweight” and “molecular weight distribution (ratio of weight averagemolecular weight to number average molecular weight)” are the valuesdetermined by gel permeation chromatography (GPC) based on polystyrenestandards. Thus, a column packed with crosslinked polystyrene gels wasused as the GPC column and chloroform was used as the GPC solvent.

PRODUCTION EXAMPLE 1

Examples of Synthesis of a Br Group-Terminated poly(butyl acrylate)

A 10-L separable flask equipped with a reflux-condenser and a stirrerwas charged with CuBr (28.0g, 0.20 mol), followed by nitrogen gaspurging. Then, acetonitrile (559 mL) was added and the mixture wasstirred on an oil bath at 70° C. for 40 minutes. Thereafter, butylacrylate (1.00 kg), diethyl 2,5-dibromoadipate (117 g, 0.325 mol) andpentamethyldiethylenetriamine [hereinafter sometimes referred to brieflyas triamine] (1.7 mL, 1.41 g, 8.1 mmol) were added and the reaction asstarted. Under heating at 70° C. with constant stirring, butyl acrylate(4.00 kg) was continuously added dropwise. In the course of drippingbutyl acrylate, triamine (8.5 mL, 7.06 g, 0.041 mol) was further added.

This reaction mixture was diluted with toluene and passed through anactivated alumina column, and the volatile matter was distilled offunder reduced pressure, whereby a Br group-terminated polymer (polymer[1]) was obtained. This polymer [1] had a number average molecularweight of 19500 and a molecular weight distribution value of 1.17.

PRODUCTION EXAMPLE 2

Example of Synthesis of a Phenol Group-Terminated poly(butyl acrylate)-1

A 100-mL reactor was charged with the polymer (1) obtained in ProductionExample 1 (50 g), potassium p-hydroxybenzoate (1.96 g, 11.1 mmol) anddimethylacetamide (50 mL). Under nitrogen, the mixture was stirred at70′ for 3 hours. The resulting reaction mixture was diluted with tolueneand passed through an activated alumina column and the volatile matterwas distilled off under reduced pressure. The resulting polymer wasdissolved in toluene and passed through an activated alumina columnagain. The toluene was then distilled off under reduced pressure,whereupon a phenol group-terminated poly(butyl acrylate) (polymer [2])was obtained. The average number of phenol groups introduced per mole ofthe polymer was 2.3 as determined by ¹H NMR analysis.

PRODUCTION EXAMPLE 3

Example of Synthesis of a Phenol Group-Terminated poly(butyl acrylate)-5

In 10 mL of dimethylacetamide was dissolved resorcinol (0.56 g, 5.13mmol) followed by addition of t-butoxypotassium (0.12 g, 1.03mmol)/t-butanol and stirring. Then, the polymer [1] (10 g) obtained inProduction Example 1 was added and the mixture was stirred under heatingat 70° C. for 2 hours. This reaction mixture was diluted with tolueneand passed through an activated alumina column, and the solvent wasdistilled off under reduced pressure. The resulting polymer wasdissolved in toluene and passed through an activated alumina columnagain and the toluene was distilled off under reduced pressure,whereupon a phenol group-terminated poly(butyl acrylate) (polymer [3])was obtained. The introduction of the phenol group into the polymer wasverified by ¹H NMR spectrometry.

PRODUCTION EXAMPLE 4

Synthesis of a Novolac Phenolic Resin

A 500-mL three-necked flask equipped with a reflux-condenser was chargedwith phenol (76 g, 0.81 mol), water (10 g), 37% aqueous solution offormaldehyde (54 g) and oxalic acid dehydrate (0.70 g) and the mixturewas refluxed for 30 minutes. Then, a supplemental amount (0.70 g) ofoxalic acid dihydrate was added and the mixture was further refluxed foranother hour. Then, the reaction system was cooled by adding 200 mL ofwater. While the resin phase was precipitated, the aqueous phase wasremoved by decantation. The resin phase was heated under reducedpressure to recover a phenolic resin. This resin was cooled to roomtemperature and comminuted.

COMPARATIVE EXAMPLE 1

The phenolic resin obtained in Production Example 4 (100 parts) wasmixed well with hexamethylenetetramine (4 parts) and the mixture washeated to cure at 150° C. for 15 minutes. The cured product was hard andbrittle.

EXAMPLE 1

The phenolic resin obtained in Production Example 4 (100 parts), thepolymer [3] obtained in Production Example 3 (15 parts), andhexamethylenetetramine (4 parts) were mixed well and heated at 150° C.for 15 minutes to give a cured product. In contrast to the productobtained in Comparative Example 1, this cured product was flexible.

EXAMPLE 2

The phenolic resin obtained in Production Example 4 (100 parts), thepolymer [3] obtained in Production Example 3 (100 parts), andhexamethylenetetramine (8 parts) were mixed well and heated at 150° C.for 3 hours to give a cured product. This cured product had rubber-likeelasticity.

INDUSTRIAL APPLICABILITY

The heat-curable composition comprising a vinyl polymer having a phenolgroup at the main chain terminus at a high rate and a phenolic resin inaccordance with the present invention gives cured phenolic resinproducts having excellent characteristics such as rubber-likeelasticity. The invention thus corrects for the brittleness of curedproducts which is the drawback of the hitherto-known phenolic resins.

1. A heat-curable composition comprising (A) a vinyl polymer having atleast one phenol group at the main chain terminus, wherein the (A)component vinyl polymer has its main chain produced by polymerizing a(meth)acrylic monomer and wherein the (a) component vinyl polymer has aratio (Mw/Mn) of weight average molecular weight (Mw) and number averagemolecular weight (Mn) as measured by gel permeation chromatography ofless than 1.8 and (B) a phenolic resin.
 2. The heat-curable compositionaccording to claim 1 wherein the (A) component vinyl polymer has itsmain chain produced by the living radical polymerization of ameth(acrylic) monomer.
 3. The heat-curable composition according toclaim 1 wherein the (A) component vinyl polymer has its main chainproduced by the atom transfer radical polymerization of a (meth)acrylicmonomer.
 4. The heat-curable composition according to claim 1 whereinthe (A) component vinyl polymer is obtained by the procedure comprising(1) producing a halogen-terminated vinyl polymer by atom transferradical polymerization and (2) converting the terminal halogen of saidpolymer to a phenol group-containing subsistent group.
 5. Theheat-curable composition according to claim 1 wherein the (meth)acrylicmonomer is a (meth)acrylic acid ester monomer.
 6. The heat-curablecomposition according to claim 5 wherein the (meth) acrylic acid estermonomer is an acrylic acid ester monomer.
 7. The heat curablecomposition according to claim 1 wherein the (A) component vinyl polymerhas a number average molecular weight of 500 to 100,000.
 8. A shapedarticle as obtained by curing the heat-curable composition according toclaim
 1. 9. The heat-curable-composition according to claim 1 furthercomprising (C) and aldehyde compound.
 10. A polymer as obtained byreacting (A) a vinyl polymer having at least one phenol group at themain chain terminus, wherein the (A) component vinyl polymer has itsmain chain produced by polymerizing a (meth)acrylic monomer and whereinthe (A) component vinyl polymer has a ratio (Mw/Mn) of weight averagemolecular weight (Mw) and number average molecular weight (Mn) asmeasured by gel permeation chromatography of less than 1.8 with (C) analdehyde compound.
 11. The polymer according to claim 10 wherein the (A)component vinyl polymer has its main chain produced by the livingradical polymerization of a (meth)acrylic monomer.
 12. The polymeraccording to claim 10 wherein the (A) component vinyl polymer has itsmain chain produced by the atom transfer radical polymerization of a(meth)acrylic monomer.
 13. The polymer according to claim 10 wherein the(A) component vinyl polymer is obtained by the procedure comprising (1)producing a halogen-terminated vinyl polymer by atom transfer radicalpolymerization and (2) converting the terminal halogen of said polymerto a phenol group-containing substituent group.
 14. The polymeraccording to claim 10 wherein the (meth) acrylic monomer is a(meth)acrylic acid ester monomer.
 15. The polymer according to claim 14wherein the (meth)acrylic acid ester monomer is an acrylic acid estermonomer.
 16. The polymer according to claim 10 wherein the (A) componentvinyl polymer has a number average molecular weight of 500 to 100,000.17. The polymer according to claim 10 wherein the aldehyde compound C isat least one member selected from the group consisting of formaldehyde,hexamethylenetetramine, paraformaldehyde, furfural, acetaldehyde andsalicyladehyde.
 18. A heat curable composition comprising the polymeraccording to claim
 10. 19. A shaped article as obtainable by curing theheat-curable composition according to claim 18.